ET: Engine (Twin) Black Shadow

Phil Talbot

Forum User
VOC Member
Hi,
could anyone give me advice on a screw that’s located on the right side of the main casting underneath.
what is it for ? And what does it do?
see photo
7EB73B30-BC55-4F51-BFB9-3D1756F19306.jpeg
 
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Phil Talbot

Forum User
VOC Member
Thanks, that explains why I’m getting oil continuously dripping from it. Any advice on how to stop it? And if I remove the screw will all the oil drain out?
thanks
 

timetraveller

Well Known and Active Forum User
VOC Member
There will be a small amount of oil so use some type of catchment system. Not enough to cause any problems. You will see from your photo that the grub screw is well punched locked and you will need some force to overcome that. I would use an impact screw driver to get it started, but carefully. You do not want to damage the aluminium round there. Sealing is easy. Just clean everything up carefully and then use your favourite sealing compound on the thread of the grub screw, making sure you do not get any up inside the drilling.
 

davidd

Well Known and Active Forum User
VOC Member
And if I remove the screw will all the oil drain out?
No. The oil line that the Factory drilled was from the small chamber behind the flywheel oil scraper that collects the oil that is flung off the flywheel that runs back to the scavenge end of the oil pump. Thus, the oil that is in the sump is drained out of the engine from the drain plug on the primary side. All of the oil in the sump has to be carried by the flywheel over a cast-in wall that has a scraper that does not touch the flywheel but guides most of the oil on the wheels to the chamber.

All the oil in this somewhat hard to get to scavenge chamber flows up to the rockers then back to the oil tank. It is only important for you to make sure that all the oil in this small chamber needs to get back to the tank to continue circulating. Without the grub screw, no oil returns to the tank.

The second revelation is that the flywheel has to lift all of the oil into the scavenging chamber from the sump. When the engine is running, this is done automatically and effortlessly by the engine. However, when starting the engine, if the flywheel is swimming in a sump full of oil, the added drag of that oil slows down the flywheels enough to prevent the engine from starting. This is called "sumping" and is universally despised by owners. Draining the oil from the sump will cure this impediment to starting and it will leave any oil in the scavenge chamber in place, so the oil should start returning to the tank fairly quickly. If the scavenging chamber is empty, it will take a long time to fill, particularly if the sump has been emptied of oil.

David
 
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